The invention relates to a an apparatus for removing liquids from the surface of a strip conveyed from a strip processing machine, more particularly a rolling stand, by means of a gas jet, having an outlet nozzle, from which the gas jet emerges, and a suctional opening, via which the gas jet can be removed by suction mixed with the liquid.
Apparatuses of the kind specified are needed to remove residues of lubricant, more particularly from high-speed rolled metal strips. After the rolling operation residues of the lubricant remain adhering to the strip, to which they were applied during rolling. If the lubricant liquid is inadequately removed, after the strip has been wound into a coil, the lubricant residues form between its individual windings a film which may cause the individual windings of the coil to telescope--i.e. become displaced axially of the reel during reeling. Moreover, as a rule the further processing of the strips requires very low residual quantities of lubricant, referred to the surface of the rolled strip.
For a considerable period attempts have been made to remove, for example, by air blasts, residues remaining on the ship after its treatment. For example, U.S. Pat. No. 3 607 366 discloses an apparatus of the art mentioned above wherein slot jet nozzles extending substantially over the width of the strip are adjusted to a predetermined inclination of their jets against the direction in which the strip to be cleaned travels. The gas jet emerging from the nozzles is directed substantially against the conveying direction of the strip. Practical tests of such apparatuses for removing residues from strips have shown that the cleaning effect achievable by said apparatuses is inadequate to completely remove residues of lubricant left on strips after each rolling operation, more particularly on strips processed on rolling stands.
An improved apparatus for the removal of liquids from the surface of a strip is disclosed in German Offen-legungsschrift DE 42 15 602 A1. In that apparatus the gas jet is blown, also via a slot jet nozzle disposed at a predetermined angle of inclination transversely of the direction in which the strip travels, on to the strip against its conveying direction, the relation between the width of the slot jet nozzle and its distance from the strip being so selected that the gas jet impinges on the strip at high velocity. At the same time, disposed at a predetermined distance in the strip conveying direction upstream of the slot jet nozzle in this prior art apparatus is a suctional removal gap via which the gas flow and the liquid mixed therewith is removed from the strip by suction.
Use in practice of the apparatus known from DE 42 15 602 A1 has shown that an adequate cleaning effect can be achieved thereby in the zone of the centre of the strip. However, it was also found that the cleaning effect is frequently inadequate in the zone of the strip longitudinal edges, the place where particularly large residues of liquid often collect.
It is an object of the invention so to improve an apparatus of the kind specified that it enables a sufficient cleaning of the strip surface to be achieved over its whole width.
This problem is solved according to the invention by the feature that in an apparatus of the kind specified the gas jet is guided over the strip in a flow directed in the direction of at least one of the lateral edges of the strip and that a suction opening is associated with that lateral edge of the strip at which the flow is directed.
According to the invention the gas jet for cleaning the surface of the strip is not blown onto the strip in a flow directed substantially against the strip conveying direction any more, as done by the apparatus of the prior art, but a lateral flow can be additionally produced which is directed at one or both of the lateral edges of the strip. The suctional removal opening is disposed laterally of the strip, so that the mixture of gas and liquid can be removed immediately alongside the strip. In this way a large volumetric flow of gas can be taken over the strip at high flow velocity. The mass impulse of the high volumetric flow is enough to remove even fairly large quantities of liquid from the surface of the strip to be cleaned and more particularly from its marginal zones.